JPS59180860A - Speed controller of magnetic disk device - Google Patents

Abstract

PURPOSE:To attain a high-speed operation of a magnetic head by obtaining a target speed based on the output of a dividing circuit which divides a cylinder pulse and produces a pulse every plural cylinder pulses and controlling the speed of the magnetic head. CONSTITUTION:A cylinder pulse (c) (a cylinder pulse defined for two tracks) which has a rise with the zero cross of the signal (b) out of double phase position signals (a) and (b) having a 90 deg. phase shift is supplied to a terminal 16. In this case, the ''pull-up'' is applied to the inputs J and K of a JK flip-flip 15. Therefore the Q output has a change of waveform like signal (f). Both the pulse (c) and the signal (f) are applied to an AND circuit 17, and the signal (g) obtained by dividing the cylinder pulse is delivered from an output terminal 18. In such a way, one pulse is obtained with four tracks. Based on this pulse, a control circuit performs a counting process, etc. Thus it is avoided that the cycle of the pulse applied to the control circuit is uselessly shortened despite the high density of tracks. This attains a high-speed operation of a magnetic head.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an improvement in a speed control device for a magnetic disk device.

[Technical background of the invention]

An example of the configuration of a conventional device will be described with reference to FIGS. 1 and 2. Figure 1 is a professional diagram of one configuration example, and the second
The figure is a time chart explaining the operation. The magnetic head 1 reads a positioning signal previously written on the medium and supplies it to the phase position signal generating circuit 1. Based on the positioning signal, the U-phase position signal generating circuit 3 generates one of the position signals a and b as shown in the second diagram when the track pitch of the medium is half the cycle of the position signal a. A cylinder pulse that rises or falls at zero cross is generated. A control circuit comprising a microprocessor, ROM, etc. counts these cylinder pulses and outputs a pre-stored target speed signal via a D/A converter.

Further, the speed signal generation circuit 6 calculates the actual speed of the magnetic helad/ by differentiating the co-phase position signal, and generates a speed signal corresponding to this. The speed signal and the target speed signal are subtracted by the summing amplifier 7, and based on this, the speed of the magnetic head 1 is controlled by the actuator driver 9 and the actuator driver 9. In other words, the actual speed obtained by the speed signal generation circuit 6 is
It is controlled by the target speed given via the data S.

When the track pitch of the medium is the '/lI period of the position signal, the position signals a and b will either rise or fall at the zero cross, as shown in FIG. 2(c). [Problems with the Background Art] The above In the conventional device, a cylinder pulse is emitted in response to the magnetic head crossing a track on the medium.
Since the number of pulses is counted and processed by a microprocessor or the like, as the density of the tracks increases, the period of the cylinder pulse becomes shorter, so there is a drawback that the magnetic head cannot be moved at high speed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a speed control device for a magnetic disk device that allows a magnetic head to operate at high speed even when the track density is increased. .

[Summary of the invention]

To achieve the above object, the present invention uses a magnetic head to read a positioning signal written in advance on a medium, and generates a cylinder signal that rises or falls in response to the magnetic head crossing a track on the medium. In a conventional device that determines the target speed of the magnetic head based on the ξ pulse and controls the speed of the magnetic head based on this target speed and the actual speed, the cylinder pulse is frequency-divided to generate a plurality of o
A cylinder pulse frequency divider circuit that emits an o pulse is provided for each pulse, and based on the output of this cylinder/ξ pulse frequency divider circuit, 1. The present invention provides a speed control device for a magnetic disk device that determines a target speed of a magnetic disk drive and controls the speed of a magnetic head.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 3 to 7. FIG. 3 is a block diagram of one embodiment, in which the same elements as in FIG. 1 are designated by the same reference numerals. Cylinder pulse generation circuit 3
A cylinder pulse frequency dividing circuit 10 for frequency dividing the cylinder pulse is provided between the control circuit q and the control circuit q. Control circuit is ROM
, a processor, etc., and counts the output of the cylinder pulse generation circuit 10 and outputs a corresponding signal (set in a ROM or the like).

FIG. 9 is a cylinder pulse circuit diagram of one embodiment of FIG. 3. A cylinder pulse is inputted from the AND circuit/terminal 7.2, and a signal from the speed signal generation circuit 6 (the signal path is not shown) is inputted from the terminal 13, and based on this, an output signal is given to the control circuit DA.

Referring to the time chart in Figure 3,
The operation of the embodiment shown in the figure will be explained. qo.

Of the phase-shifted co-phase position signals a and b, the cylinder pulse ξ c that rises at the zero cross of the position signal (per cylinder pulse per 2 tracks) is input to one of the inputs of A and ND circuit l/. A signal d used, for example, in the speed signal generating circuit 6 is applied to the input terminal /3 at the AND circuit circuit/end. Then, AND
A signal e is output from the circuit/terminal/gate. In this way, the cylinder pulse is frequency-divided (in this embodiment, there is one pulse for one pulse).

Thus one pulse per l track is obtained,
Processed in the control circuit.

FIG. 6 is a circuit diagram of the embodiment shown in FIG. 3, which is composed of seven AND circuits for each cylinder noculus.

The J input of the JK freesive flop lS and the input
u1l Up" is input, and the cylinder/ξ pulse is input with negative logic to the black and Tsuk inputs via terminal /6. Then,
&-! to one input terminal of AND circuit/7. , rKf]nozzoflo, , is given to the Q output, and the cylinder pulse ξ is given to the other input terminal. AND circuit/7 output terminal/
g is connected to the input terminal of the control circuit t.

Referring to the time chart in Figure 7,
The operation of the embodiment shown in the figure will be explained. 90' Of the two-phase position signals a and b whose phases are shifted, the cylinder 7 signal C that rises at the zero cross of the position signal (, per 2 tracks/
Cylinder 7 (no odor) is applied to terminal /A. At this time, since "Pu1l Up" is applied to the J input of the J4 flip-flop, Zo/3, the waveform of the Q output changes as shown in the signal f shown in FIG. Since the cylinder pulse C and the signal f are each given to the AND circuit /7, the output terminal /g of the AND circuit /7 outputs a signal g obtained by frequency-dividing the cylinder pulse ξ. In this way, one pulse is obtained for each track, and the control circuit performs counting and other processing based on this pulse.

Note that by combining counters, flip-flops, gates, etc. after the AND circuits shown in FIGS. 7 and 6, an n-channel 1
．． It is also possible to obtain one pulse per hour.

〔Effect of the invention〕

As described above, according to the present invention, a positioning signal written on a medium in advance is read by a magnetic head, and a cylinder signal that rises or falls in response to the magnetic head crossing a track on the medium. The conventional device calculates the target speed of 7F for magnetism based on the above, and controls the speed of the magnetic head based on this target speed and the actual speed.
We installed a cylinder pulse frequency divider circuit that divides the cylinder pulse frequency and generates one e pulse for each of multiple ξ pulses, and based on this, the target speed of the magnetic head is determined, so that the tracks can be arranged at a high density. Even if the pulse period applied to the control circuit is not shortened unnecessarily (2.), a speed control device for a magnetic disk device that can operate at a high speed can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a configuration example of a conventional device, FIG. 2 is a time chart explaining the operation of the configuration example of FIG. 1, and FIG.
The figure is a block diagram of an embodiment of the present invention, FIG. 7 is a circuit diagram showing an example of the configuration of the cylinder pulse frequency divider circuit of the embodiment of FIG. 3, and FIG. A time chart explaining the operation of one embodiment, FIG. 6 is a circuit diagram showing another example of the configuration of the cylinder pulse frequency dividing circuit of the embodiment shown in FIG. 3, and FIG. This is a time chart explaining the operation of one embodiment. // , /7...A117D circuit, /S...,T
K flip flop. Applicant's agent Kiyoshi Inomata Figure 5 Figure 7

Claims (1)

[Scope of Claims] A magnetic head that reads a positioning signal written in advance on a medium, a circuit that generates a speed signal corresponding to the actual moving speed of the magnetic head based on this positioning signal, and A circuit that generates a cylinder pulse that rises or falls in response to the magnetic head crossing a track on the medium based on a signal, and a circuit that responds to a target value of the moving speed of the magnetic spatula P based on this cylinder pulse. A speed control device for a magnetic disk drive comprising: a target speed circuit for generating a target speed signal; and means for operating the magnetic spatula r on the medium based on the speed signal and the target speed signal. a cylinder that rotates around and emits an o pulse, one for each of the plurality of pulses of the cylinder pulse;
1. A speed control device for a magnetic disk drive, comprising: an a pulse frequency divider circuit; and wherein said target speed circuit generates said target speed signal based on an output of said cylinder/ξ pulse frequency divider circuit.